Genome Sequence of Oenococcus oeni UNQOe19, the First Fully Assembled Genome Sequence of a Patagonian Psychrotrophic Oenological Strain.

Oenococcus oeni UNQOe19 is a native strain isolated from a Patagonian pinot noir wine undergoing spontaneous malolactic fermentation. Here, we present the 1.83-Mb genome sequence of O. oeni UNQOe19, the first fully assembled genome sequence of a psychrotrophic strain from an Argentinean wine.

Influence of Candida pulcherrima Patagonian strain on alcoholic fermentation behaviour and wine aroma.

The use of selected Saccharomyces and non-Saccharomyces strains as mixed starters in winemaking would have advantages over the traditional spontaneous fermentation, producing wines with predictable and desirable characteristics. The aim of this study was to evaluate the impact of metabolic interactions between Patagonian indigenous Saccharomyces cerevisiae MMf9 and beta-glucosidase producer Candida pulcherrima V(6) strains on alcoholic fermentation behaviour and wine aroma Three inoculation strategies, simultaneous, sequential and final, were assayed at laboratory-scale fermentations using Muscat d'Alexandrie grape juice as substrate. The fermentation and yeast growth kinetics as well as the physicochemical and the sensory quality of wine were evaluated. Results evidenced that the sequential inoculation is the most adequate strategy of strains combination. The kinetic behaviour of sequential fermentation was similar to a successful spontaneous fermentation and its wine showed differential aromatic quality as evidenced through PC analysis using physicochemical and aromatic composition data. This wine presented the highest total concentration of higher alcohol, esters and terpenols and the strongest fruity and floral aroma.

Patagonian wines: the selection of an indigenous yeast starter.

The use of selected yeasts for winemaking has clear advantages over the traditional spontaneous fermentation. The aim of this study was to select an indigenous Saccharomyces cerevisiae yeast isolate in order to develop a regional North Patagonian red wine starter culture. A two-step selection protocol developed according to physiological, technological and ecological criteria based on killer interactions was used. Following this methodology, S. cerevisiae isolate MMf9 was selected among 32 indigenous yeasts previously characterized as belonging to different strains according to molecular patterns and killer biotype. This isolate showed interesting technological and qualitative features including high fermentative power and low volatile acidity production, low foam and low sulphide production, as well as relevant ecological characteristics such as resistance to all indigenous and commercial S. cerevisiae killer strains assayed. Red wines with differential volatile profiles and interesting enological features were obtained at laboratory scale by using this selected indigenous strain.

Candida patagonica sp. nov., a new species of yeast from cellar surfaces.

A novel anamorphic yeast species belonging to the genus Candida has been isolated from cellar surfaces in North Patagonia. Morphological and physiological observation and phylogenetic analysis were performed. Pseudomycelium was plentifully produced. No sexual reproduction was observed. From sequence analysis of the 26S rDNA D1/D2 region, Candida bituminiphila and Zygoascus hellenicus were the closest species with 40 and 79 bp substitutions, respectively. C. bituminiphila differed physiologically from the novel species in its ability to assimilate sucrose and erythritol, in not fermenting any sugars, in growing without some vitamin compounds, and in growing at 40 degrees C. All these data support the hypothesis that the new yeast, named Candida patagonica, is a novel species related to C. bituminiphila. The type strain is UNCOMA 159.5 (= CECT 12029 = CBS 10443).

Patagonian wines: implantation of an indigenous strain of Saccharomyces cerevisiae in fermentations conducted in traditional and modern cellars.

In this work we evaluate the implantation capacity of the selected S. cerevisiae indigenous strain MMf9 and the quality of the produced wines in a traditional (T) and a modern (M) cellar with different ecological and technological characteristics in North Patagonia (Argentina). Red musts were fermented in 10,000 l vats using the indigenous strain MMf9 as well as the respective controls: a fermentation conducted with a foreign starter culture (BC strain) in M cellar and a natural fermentation in T cellar. Since commercial S. cerevisiae starters are always used for winemaking in M cellar and in order to compare the results, natural fermentations and fermentations conducted by the indigenous strain MMf9 were performed at pilot (200 l) scale in this cellar, concomitantly. Thirty indigenous yeasts were isolated at three stages of fermentation: initial, middle and end. The identification of the yeast biota associated to vinifications was carried out using ITS1-5.8S-ITS2 PCR-RFLP. The intra-specific variability of the S. cerevisiae populations was evaluated using mtDNA-RFLP analysis. Wines obtained from all fermentations were evaluated for their chemical and volatile composition and for their sensory characteristics. A higher capacity of implantation of the indigenous MMf9 strain was evidenced in the fermentation carried out in M cellar (80% at end stage) than the one carried out in T cellar (40%). This behaviour could indicate that each cellar differs in the diversity of S. cerevisiae strains associated to wine fermentations. Moreover a higher capacity of implantation of the native starter MMf9 with regard to the foreign (BC) one was also found in M cellar. The selected indigenous strain MMf9 was able to compete with the yeast biota naturally present in the must. Additionally, a higher rate of sugar consumption and a lower fermentation temperature were observed in vinifications conducted by MMf9 strain with regard to control fermentations, producing wines with favourable characteristics. Even when its implantation in T fermentation was lower than that observed in M one, we can conclude that the wine features from MMf9 fermentations were better than those from their respective controls. Therefore, MMf9 selected indigenous strain could be an interesting yeast starter culture in North Patagonian wines.

Combined use of killer biotype and mtDNA-RFLP patterns in a Patagonian wine Saccharomyces cerevisiae diversity study.

The aim of this work was to characterize the indigenous wine Saccharomyces cerevisiae diversity within the Argentinean Patagonia. Two cellars with particular enological practices located in different winegrowing areas were selected and 112 indigenous S. cerevisiae isolates were obtained from spontaneous red wine fermentations carried out in them. Thirty-five and 19 patterns were distinguished among the total indigenous isolates using mtDNA-RFLP and killer biotype analysis, respectively. The combination of both typing techniques rendered a higher variability with 42 different patterns, i.e. 42 strains, evidencing a great diversity in S. cerevisiae populations associated with spontaneous red wine fermentations in Northwestern Patagonia. The analysis of the relatedness among strains using Principal Coordinates Analysis from combined data allowed the clustering of the strains into two populations significantly related to their origin fermentations. The combined use of the mtDNA-RFLP analysis together with the killer biotype method proved to be a powerful tool in the fingerprinting of the enological S. cerevisiae strains.